Resilient shell structure and method of making it



Jan. 9, 1968 G. M GOWAN 3,352,127

RESILIENT SHELL STRUCTURE AND METHOD OF MAKING IT Filed Aug. 27, 19 4 IINVENTOR. Graeme McGowan his Aftorne United States Patent 3,362,127 RESILIENT SHELL STRUCTURE AND METHOD OF MAKING IT Graeme McGowan, Cortez, Colo., assignor to Resilient Shells, Inc., Cortez, Colo., a corporation of Colorado Filed Aug. 27, 1964, Ser. No. 392,503 4 Claims. (Cl. 52-747) Resilient shell structures are constructed of rigid or semi-rigid panels arranged to provide compound curvature or angularity and joined to each other and to a support by elastic joints which are securely bonded to the panel edges by an elastic or rubbery cement. The elastic joints that tie the structure together also provide a resiliency to compensate for forces of expansion and contraction, uneven loading, wind, shock, seismic effects, etc. This invention provides improvements in making structures of this type.

In my US. Patent 3,077,702 a particular type of resilient shell structure is described in which H-shaped rubbery strips were used, their outer portions being secured to adjacent panel edges and their mid portions being positioned between said adjacent edges. This technique has been successfully employed, but great difficulty was encountered in large structures in the application of the cement-coated rubbery strips to the bowed panel edges and the holding of said edges in the desired position till the cement was set or cured. The object of this invention is to provide a new and improved method and means for providing and securing the elastic or rubbery joints in the resilient shell structure. Other objects will become apparent as the detailed description of the invention proceeds.

In this invention a group of panels providing compound curvature are temporarily held in the desired adjacent spaced relationship by improved T-clamps having heads no wider than the bolt-like stem of the T-clamp, the heads preferably having lugs thereon for entering pre-formed holes adjacent panel edges where corners come together so that the tightening of the T-clamp not only securely holds the adjacent panels but accurately positions them for receiving my unique rubber-cement-coated rubbery strips. The first rubbery strip has a cross-section somewhat resembling an iron rail: it has a center web portion whose thickness is the approximate distance between adjacent panels and whose height is approximately the panel thickness, it has lower flanges designed to fit snu-gly' against the edges of the panels during the cementing process, and it has an upper rounded bead portion designed so that it can be deformed sufficiently to be pushed through the space between adjacent panels (particularly when coated with a syrupy rubber cement that serves as a lubricant) and so that when it is thus positioned, the bead bears against adjacent panel edges and holds the cement-coated flanges tightly in place against the opposite panel edges until the rubber cement has thoroughly set or cured. Then the T-clamps are loosened, rotated 90 and removed, and the corner spaces are caulked, preferably by cutting short lengths of the rubbery strip to fit the open space, coating it with rubber cement and pushing the bead portion through the slot so that said head again serves to hold the flanges in place while the cement is curing. Finally a second rubbery strip is applied from the other side of the structure: in cross-section, this second strip has a mid-portion that serves as a stressed hinge-clamp, flanges on each side of the mid-portion, and a curved opening between the flange. When the second strip is coated with rubber cement on the bottom of the flanges and around the curved opening, the curved portion may be pushed over the head so that the bead will hold the flanges firmly against the panel edges till the cement cures and so that the bead itself is firmly secured by a rubbery bond to the second strip.

In my preferred structure the panels are shaped and arranged so that two corners come together adjacent an unbroken panel edge. In other words, I efiect juncture of only three panels at each corner over most of the structural area, and particularly at its top. The T-clamps are preferably provided with a ring or other suitable tie-structure so that ropes or cables may pull the shell structure to the desired configuration before the rubbery strips are applied. Such cables may be drawn against the outer side of the shell structure instead of or in addition to using ties on the T-clamps. The rubbery joints between adjacent panels, when constructed as herein described, are remarkably easy to install, are most economical, and at the same time are surprisingly strong, flexible and permanent.

The invention will be more readily understood from the following detailed description of a preferred example thereof read in conjunction with the accompanying draw ings which form a part of this specification and in which:

FIG. 1 is a schematic representation of a geodesic dome roof corresponding to that of FIG. 2 of US. 3,077,702 (except for the different panel shapes, sizes and arrangement).

FIG. 2 is a detail showing my T-clamps holding panel edges in place where three panels come together.

FIG. 3 is a detail showing how the top bare of the T-clamp may be rotated for inserting it in operative position or removing it.

FIG. 4 is a sectional view of my improved T-clamp, per se, showing how its lugs co-operate with holes in the panels.

FIG. 5 is an isometric view of a short first rubbery strip.

FIG. 6 is a similar view of a short length of my second rubbery strip.

FIG. 7 is a cross-section of my finished rubbery joint.

FIG. 8 is a detail showing the bead being deformed and pushed between adjacent panels while the latter are being held by T-clamps.

The resilient shell structure of this example is a geodesic dome-shaped roof or shelter. Actually, for a structure about 50 by 50 feet this shell would require upwards of a hundred panels most of which would be pseudo rectangular, about 4 by 8, but for simplicity and ease of understanding a fewer number will be herein described. Referring to FIG. 1, curved angle-steel supports are provided along lines AB, BC, CD, and DA, the peripheral edge of such steel support being equivalent in this description to a panel edge. The panels employed in this case may be approximately two to three times as long as they are wide, and they are arranged so that four or more corners will not come together at a single point, there being always one uninterrupted panel or support edge opposite the juncture of adjacent panel corners. While this feature and the feature of using relatively large bowed panels in the center of the structure constitutes an improvement on the structure shown in 3,077,702, other aspects of the present invention are applicable to resilient shell structures and methods of making them regardless of the size or shape of panels employed; such panels may be triangular, pseudo rectangular, pentagonal, hexagonal or any other geometric shape for fitting together with a small space therebetween so, with the requisite compound curvature or angularity, they can be held by rubbery joints to form resilient shells.

After the peripheral supports are provided, a row or two of panels, e.g. panels 10, 11, 12, 13, 14, 15, 16, and 17 are secured in place by T-clamps 21 as illustrated in FIG. 4. Each T-clamp has a bolt portion 22 which is length of my externally threaded and which serves as a spacing element to prevent adjacent panels from coming too close together. It has a top bar 23 which is no wider than the bolt portion 22 and it has downwardly extending pins or lugs 24 which are preferably tapered and which cooperate with pre-formed holes 25 in the panel edges to insure that said panels will be exactly the right spaced relationship. These T-clamps may be pushed up between adjacent panels, then rotated 90 (see FIG. 3), positioned so that lugs 24 are in holes 25, and then secured by tightening the lower wing-nut 26, a washer 27 preferably being interposed between the wing-nut and the lower edges of panels such as 12 and 13. The lower end of the bolt portion 22 is preferably provided with a tiestructure such as ring 28 through which ropes or cables may be passed to hold the shell in the desired position while the rubbery joints are being applied, ring 28 also serving as a handle to facilitate the insertion, turning and removal of the T-clamps. Instead of or in addition to ropes or cables (not shown) co-operating with rings 28 I may keep the group of panels in the proper bowed position by one or more hold-down cables 28A bearing against the exterior surface of the shell structure.

When the group of panels is thus temporarily but firmly held in the desired configuration with spaces between adjacent edges uniformly fixed as described in connection with FIGS. 1 to 4, I am ready to apply the rubbery joints along panel edges between the T-clamps. The rubbery joints consist essentially of lower and upper continuous strips of defined configuration which are securely but resiliently bonded to each other as well as to edges of adjacent panels as shown in FIGS. to 8 inclusive. The strips 29 and 34 may be of any rubbery material having the required strength throughout the anticipated temperature range, and being substantially immune to aging, oxidation, effects of sunlight, etc. I prefer to employ neoprene strips of the type commonly used in the building trade, but natural or synthetic rubbers may be adequate for many installations, and the architect or engineer may specify the required properties for any given installation. The rubber cement or bonding agent will depend on the composition of the panels and the strips, respectively, and in this example I employ a syrupy polysulfide cement which is prepared by mixing a polymerizable monomer with a polymerization catalyst. Specifically I use Product Research Companys PRC 250 for bonding the neoprene strips to panels of acrylic plastic, the panel edges being buffed and all surfaces being properly primed before the application of the syrupy cement mixture itself. For the metal edges of the base the preferred primer is PRC Primer No. 1 while for the neoprene strips and the panel edges the preferred primer is PRC 1523, the primers being allowed to cure for at least about 16 hours before the cement is applied. No invention is claimed in the compositions of the rubbery materials, primers or cements per se and no further description thereof is necessary.

A length of strip 29 is cut which will extend from one T-clamp to another. Strip 29 has a web portion 30 of which the thickness is approximately the panel thickness, each in this example being about A inch. Integral with the base of web portion 30 are flanges 31 and 32 which in this example are about inch thick and about inch wide. These flanges are slightly upwardly inclined toward their outer edges so that when the flange portion adjacent the web is held against the lower panel edge, the entire surface of the flange will be urged against the lower panel edge. Integral with the top of web 30 is a curved bead portion 33. When the top surfaces of flanges 31 and 32, the side surfaces of web 30 and the surface of bead 33 are coated with the syrupy polysulfide cement, the bead 33 may be pushed up between adjacent panel edges by virtue of its being deformed and lubricated by the cement. Once it is through the slot the lower corners of the bead (at its juncture with the web) are held in place by the upper corners of adjacent panels so that the bead actually holds the cement-coated flange surfaces against the lower panel edges until the cement has cured.

When the lower strip 29 is securely bonded to adjacent panels the T-clamps are removed by loosening the wing nuts 26, lifting lugs 24 out of holes 25, rotating the bars 23 through and then downwardly withdrawing them. The openings left in the corner areas are then caulked, preferably by cutting short lengths of strips 29 and applying it in the manner described for the long strips. The structure is now strong enough for applying the second or upper rubbery strip 34. Strip 34 has a central upper hinge-clamp portion 35, a flange 36 integral with one side thereof and a flange 37 integral with the other side thereof. Below central portion 35 and between the flanges 36 and 37 there is a curved opening 38 which is normally smaller than bead 33 but which snugly fits bead 33 when portion 35 is flexed to enable such a fit, at which time the lower edges of flanges 36 and 37 will be held against the top edges of adjacent panels. Thus when the lower areas of the top strip, and of course bead 33 and panel edges adjacent thereto, are coated with the polysulfide cement and pressed together, the stressing of the hinge-clamp portion holds the flanges in place till the cement cures. Here, as in the cementing of the lower strip, it is important to remove any air pockets that may be formed; this may be accomplished by running a roller or a high speed vibrator back and forth along the flanges while the cement is in its very fluid condition. Air pockets may be minimized by rolling the strips into place instead of applying them vertically.

The final rubbery joint is shown in FIG. 7 from which it will be noted that there is a remarkably strong rubbery bond between 32 and 12, 31 and 13, 36 and 12, 37 and 13, and 33 and 38 as well as on both sides of web 30 of strip 29. With such rubbery joints between adjacent panels throughout the structure a resilient shell is obtained in which all stresses and forces are inwardly balanced. No supporting or stiffening means are required other than the compound curvature or angularity and the stiffness of the panels per se.

While a specific embodiment of my invention has been described in considerable detail, it should be understood that this is only by way of example. Other modifications, alternative materials and procedures, and different shell structure designs will be apparent from the foregoing description to those skilled in the art.

I claim.

1. The method of constructing a resilient shell structure wherein panels are held in adjacent spaced relationship by rubbery joints, which method comprises:

(a) temporarily holding a group of panels in the desired adjacent spaced relationship by T-clamps positioned where corners of the panels come together, the diameter of the bolt-portion of the T-clamp being approximately the distance between adjacent panels,

(b) sliding into the spaces between the panels a strip of rubbery material coated with a syrupy cement which initially serves as a lubricant, said strip having (i) a rounded bead portion that may be deformed when the strip is slid into place,

(ii) a web portion whose height is approximately the thickness of the panels and whose width is approximately the distance between the panels, and

(iii) flanges which are to be cemented to the edges of the panels,

(c) removing air pockets from space between flanges and panel edges,

(d) removing the T-clarnps after the cement has cured,

and

(e) caulking the corners after the T-clarnps have been removed, the bead portion of the strip serving to hold the cement-coated flanges against the edges of the panels until the cement has cured.

2. The method of claim 1 which includes the subsequent step of applying over the protruding bead of the strip a second rubbery strip coated with cement, the second strip being shaped to fit snugly over the bead and thus to hold its cement-coated flanges against the edges of the panels until the cement cures.

3. The method of claim 1 which includes the steps of providing holes in the panels adjacent positions where corners meet and providing lugs on the T-clamps shaped to fit into said holes while the T-clamps are in use.

4. The method of claim 1 which includes the step of effecting juncture of only three panels at each corner over most of the structure area.

References Cited UNITED STATES PATENTS Re. 13,945 7/ 1915 McCormick 296-93 2,625,715 1/1953 Beck 52208 3,077,702 2/ 1963 McGowan 5281 FOREIGN PATENTS 1,105,961 7/1955 France. 1,252,603 12/ 1960 France.

HENRY C. SUTHERLAND, Primary Examiner.

PRICE C. FAW, Assistant Examiner. 

1. THE METHOD OF CONSTRUCTING A RESILIENT SHELL STRUCTURE WHEREIN PANELS ARE HELD IN ADJACENT SPACED RELATIONSHIP BY RUBBERY JOINTS, WHICH METHOD COMPRISES: (A) TEMPORARILY HOLDING A GROUP OF PANELS IN THE DESIRED ADJACENT SPACED RELATIONSHIP BY T-CLAMPS POSITIONED WHERE CORNERS OF THE PANELS COME TOGETHER, THE DIAMETER OF THE BOLT-PORTION OF THE T-CLAMP BEING APPROXIMATELY THE DISTANCE BETWEEN ADJACENT PANELS, (B) SLIDING INTO THE SPACES BETWEEN THE PANELS A STRIP OF RUBBERY MATERIAL COATED WITH A SYRUPY CEMENT WHICH INITIALLY SERVES AS A LUBRICANT, SAID STRIP HAVING (I) A ROUNDED BEAD PORTION THAT MAY BE DEFORMED WHEN THE STRIP IS SLID INTO PLACE, (II) A WEB PORTION WHOSE HEIGHT IS APPROXIMATELY THE THICKNESS OF THE PANELS AND WHOSE WIDTH IS APPROXIMATELY THE DISTANCE BETWEEN THE PANELS, AND (III) FLANGES WHICH ARE TO BE CEMENTED TO THE EDGES OF THE PANELS, (C) REMOVING AIR POCKETS FROM SPACE BETWEEN FLANGES AND PANEL EDGES, (D) REMOVING THE T-CLAMPS AFTER THE CEMENT HAS CURED, AND (E) CAULKING THE CONERS AFTER THE T-CLAMPS HAVE BEEN REMEOVED, THE BEAD PORTION OF THE STRIP SERVING TO HOLD THE CEMENT-COATED FLANGES AGAINST THE EDGES OF THE PANELS UNTIL THE CEMENT HAS CURED. 